Detonating cord is used extensively in the petroleum exploration and production industry to initiate the detonating of explosive materials in various types of downhole tools, such as perforating tools, setting tools, and the like. The borehole sites at which such tools and associated detonating cord are used are scattered worldwide, as are the relevant manufacturing, supply and service facilities. Consequently it is highly desirable that such tools, as well as the associated detonating cord be shipped by air from the supply facility location to the location of the using facility. However, the regulations governing the shipment of explosive materials by air are quite stringent. Basically, the regulations require that the explosive materials be packaged such that any ignition or detonation shall be confined to that container and will not propogate to another container.
U.S. Pat. No. 4,586,602 and U.S. Pat. Application Ser. No. 07/110,227 disclose detonating cord transport systems that meet the above mentioned air shipping regulations for explosive materials. These systems disclose the use of a severing medium between cord portions which are located in proximity to each other in order to cause the cord to sever itself upon the occurrence of any detonation. The actual detonating cords which have been used in these systems are detonating cords having a soft jacket.
Upon further investigation, it has been found that a severing medium is not needed between the detonating cord portions in a system wherein the detonating cord packaged has a metal jacket. In fact it has been found that in a packaging system for a detonating cord having a metal jacket, the use of a severing medium does not effectively work to terminate a detonation which may occur.